Organohalophosphines



United States Patent 2,934,564 ORGAN OHALOPHOSPHINES Anton B. Burg, LosAngeles, and Ross L Wagner, Montebello, Calit'., assignors, by mesneassignments, to American Potash & Chemical Corporation, a corporation ofDelaware Application November 8, 1957 Serial No. 695,225

13 Claims. (Cl. 260-543) No Drawing.

This invention relates in general to the preparation of alkyl and arylsubstituted halophosphines and more particularly to compounds of thegeneral formula R PX and RPX whereinR represents an alkyl or aryl groupand X represents chlorine, bromine or iodine and compounds of the typeR(PX where R is a polymethylene or arylene group.

Phosphinoborine compounds of the general type has a spontaneous ignitiontemperature in excess of 240 C. and certain samples of this type ofcompound have shown spontaneous ignition temperatures as high as 300 C.It is also an excellent dielectric and thus finds utility wherechemically and thermally stable dielectrics are needed.

The ignition temperatures of most of these compounds decrease somewhatas the alkyl or aryl chains increase in size, thus rendering thecompounds more hydrocarbonlike. However, the ignition temperature stillremains considerably in excess of those of most of the organic polymericmaterials. The compound [(CH PBH has a melting point of 87 C. When thehydrocarbon chain on the phosphorus is increased in length, the meltingpoint decreases. For example, the compound draulic fluid which has highresistance to the effects of elevated temperatures and resists chemicalattack, these liquid phosphinoborine polymers find utility.

A variety of methods has been set forth in the afore mentioned copendingapplication for the manufacture of these phosphinoborine polymers, butsimpler synthetic procedures have been sought.

It is therefore an object of this invention to provide a process ofpreparing new compounds which are valuable as intermediates in thepreparation of the aformentioned phosphinoborine polymers.

It is a further object of this invention to provide a method for themanufacture of compounds, these compounds having the general-formulae RPX and RPX wherein R represents the same or different alkylor arylsubstituents and X represents bromine, chlorine or iodine, and compoundsof the type X PR-PX where R is a polymethylene tor arylene radical,these methods being procedures which may be readily practiced withavailable reagents.

Other objects and advantages of this invention, if not specifically setforth, will become apparent during the course of the discussion whichfollows.

Generally, it has been found that where a single mole of anaminophosphine of the type R PNR' or RP(NR' is reacted with 2 moles and4 moles respectively of HX, a product is obtained having the generalformula R PX or RPX Where a single mole of a compound of the type R N)PRP(NR' Rbeing arylene or polymethylene, is treated with 8 moles HX, aproduct is obtained having the general formula X PRPX More particularly,a method of making deceptively simple compounds of the alkyl and arylhalophosphinetype [especially (CI-1,);PC1, (CH PBr, (CH PI, CH PC1 CHPBr and CH PI for their value as intermediates in'the manufacture ofcertain stable phosphinoborine compounds has long been sought. It hasnow been discovered that the formation of certain of these intermediatesas well as compounds having larger organic radicals bonded to the P atommay be represented generally by the formulae,

Where an aromatic aminophosphine compound of the type p-C H (P[N(CH or apolymethylene aminop-hosphine of the type (CH ),,(P[N(CH where x=4-6 isused as a precursor, each amino substituent on each phosphorus will bereplaced by a halogen; and the equation representing preparation of theproduct is analogous to the second of the two set out above:

In applicants preliminary tests, the treatment of compounds of the type(CHg) NP(CH with slightly more than two equivalents of HCl yielded aproduct which, while possibly containingtthe desired-(CH PC1, alsocontained such an excess of I-lCl that it was impossible to isolate thedesired dialkyl chlorophosphine. The excess HCl could not be removedeither by distillation methods or by reaction with a tertiary amine.However, it has now been found that when the quantities of R NPR and HClare adjusted so that exactly one equivalent of the former is present fortwo of the latter, the compound having the formula R PC1 is cleanlyobtained without necessity for the aforementioned removal of excess HCl.

Similarly, in preparing other compound of the type R PX, RPX and R( PXit has been determined that the quantity of hydrohalogen acid must becarefully controlledas dictated by the equations above.

Preparation of the amin0-0rgan0phosphines used as precursors may beaccomplished through the method set forth in copending applicationSerial No. 593,365, filed June 25, 1956 for Manufacture ofAminophosphines. Alternatively, amino-halophosphines may be prepared bythe method first described by Michaelis, Ann, 326,129 (1903) andthereafter treated with a Grignard reagent to yield the desiredamino-organophosphine precursor. For illustrative purposes, thepreparation of aminoorganophosphines is set out in certain of theexamples.

As is apparent from these examples, the symbol R in the general formulaeRPX and R PX represents any hyirocarbon radical capable of forming aGrignard or organolithium reagent and the symbol R in R(PX must be analiphatic or aromatic radical which may form a double Grignard ororganolithium reagent. In the compound R(PX R maybe (C H or (CH wherex=4-6. t v

Various examples are set forth .below by way of illus tration, but arenot to be deemed as imposing limitations assasee A e on the scope of theinvention other than as set forth in the appended claims.

EXAMPLE I A 5.284 mole sample of (CH NP(CH and 7.912 mmoles of HCl werecombined in a 50 ml. vertical reaction tube attached to the high-vacuumapparatus, with slow warming from 78 C. to room temperature. Thevolatile product now had physical properties indicative of purity; forexample, the molecular weight of the 80 percent saturated vapor wasmeasured as 97.9; calcd, 96.5. The melting range was narrow: 1.4 to -l.0C. The vapor tensions also were consistent with purity; the values forthe solid, shown in Table 1 determine the equation log P=12.1408-2887/T, while those for the liquid (Table 2) are fairlyconsistent with the equation log P =7.884--l722/T. This would indicatethe normal B.P. as 71 C., but since the Trouton constant (22.9ca1./deg.mole) is a little above normal, the true B.P. probably isnearer to 73 C. From the two equations, the heat of fusion is calculatedas 5.33 kcaL/mole and the M.P. as 2.0 (obsd.1.4 to 10 C.).

The aminolysis of (CH PCl was repeated, using an almost pure sample(0.437 mmole) with 0.947 mmole of (CH NH. The result was a 92 percentyield of (CH NP(CH and an analysis of the by-product (CH NH Cl gave thecalculated 0.437 mmole of Cl. This experiment completes the proof of theformula (CH PCl.

Table 1 [Vapor tensions of solid (CH hPCll l( C.) 39. 8 34. O -27. 4-18. 6 -12. 25 -5. 5 Pmm (013511.) 0. 57 1. 19 2. 44 6. 31 11. 92 22. 62Pmm (calcd.) 0. 59 1. 17 2. 47 6. 31 11. 91 22. 63

Table 2 [Vapor tensions of liquid (CH3)2PO1] t( C.) O. 2. 4 9. 4 15. 319. 8 21. 7 33. 1 Pmm (0bSd.) 34. 6 39. 56. 6 74. 9 91. 5 99. 5 168. 7Pmm (calcd.) 34. 7 39. 4 56. 2 74. 9 92. 6 100. 9 166. 5

EXAMPLE II Dimethylamine in the amount of 177 g. (3.92 moles), whenbubbled into 273 g. (1.99 moles) phosphorus tri- 4 EXAMPLE III Using thesame procedure as above but using 392 g. (8.70 moles) dimethylamine, 280g. (2.04 moles) phos phorus trichloride, and 2700 ml. diethyl ether, a212.4 g. (1.37 moles) quantity of bis(dimethylamino)chlorophosphine,[(CH N] PCl, (13. 937 C.) was prepared in 67 percent yield.

To a well-stirred solution of 17.5 g. (0.113 mole) of the [(CH N] PCl in400 ml. diethyl ether maintained at 75 C. was added 0.117 mole of C H Liin 175 ml. diethyl ether. The reaction mixture was allowed to Warm toroom temperature. After removing ether by distillation, 250 ml.petroleum ether was added to precipitate lithium salts and the mixturewas filtered in a nitrogen atmosphere. Fractional distillation of thefiltrate yielded 17.5 g. (0.089 mole) bis(dimethylamino)phenylphosphine,C H P[N(CH B. 42-4 C. A 79 percent yield of liquid was obtainedanalyzing N 14.2; calc. for CmH NzP, N, 14.28.

A 926.7 cc. (41.37 mmoles) quantity of anhydrous HCl was absorbed by asolution of2.0327 g. (10.35 mmoles) C H P[N(CH in 15 ml. diethyl ethercooled to -10i10 C. Complete adsorption which rechloride in 1000 ml. ofdry diethyl ether under a nitrogen atmosphere, gave a precipitate ofdimethylammonium chloride. During the reaction, the vessel was cooled inan ice bath. The ethereal filtrate was fractionally distilled to yield191.3 g. (1.32 moles) dimethylaminodichlorophosphine, (CH NPCl (67percent), B.P. 147 C 21.4 g. (p-CH C H PN(CH was prepared in 19.8percent yield from 61.0 g. (0.42 mole) (CH NPCl in a Well stirredsolution and 0.84 mole p-CH C H MgBr,

each in 1000 ml. diethyl ether. Purification of the prod- (assay 95.2percent) in a 35 ml. diethyl ether. The byproduct was determined to haveformed in 98.3 percent yield by chloride analysis and the product,

was isolated by fractional distillation. A total of 5.60 g. of productdi-p-tolylchlorophosphine, B. 165.-8 C. was obtained in 70.6 percent.yield.

quired 45 minutes was determined by .the observation that the vaporpressure of the mixture was less than 0.5 mm. on lowering thetemperature of the mixture to 78 -C. The by-product dimethylammoniumchloride was filtered off and analyzed for chlorine (21.6 mmoles found).The solvent was stripped from the ethereal filtrate and the residue wassubjected to fractional condensation. In a trap at 10 C. 1.1650 g. (6.50mmoles) of C H PCl (62.8 percent yield) was obtained analyzing 38.1percent chlorine (calc. 39.6 percent). The infrared spectrum of theproduct was identical to that of an authentic sample.

EXAMPLE IV To a well-stirred solution of 34.0 g. (0.220 mole) [(CH N]PCl in 300 ml. diethyl ether maintained at -78 C. was added 0.219 moleof C I-I MgBr in 300 ml. diethyl ether. The reaction mixture was allowedto warm at room temperature and filtered in a nitrogen atmosphere.Fractional distillation of the filtrate yielded 11.7 g.bis(dimethylamino)propylphosphine,

A 32 percent yield ofliquid was obtained.

Using the procedure of Example III, the 0.070 mole C H P[N(CH wastreated with 6377 cc. (0.28 mole) anhydrous HCl in 200 ml. diethylether. After removal of the by-product, dimethylammonium chloride, thesolvent was stripped from the filtrate. The product,

C H PCl was isolated by fractional distillation at 2 C.

EXAMPLE V The yellow organolithium solid p-Li C H in the amount of 18.7g. (0.208 mole) was slurried in 200 ml. petroleum ether and added over aperiod of 15 minutes with vigorous stirring to a solution of 105.2 g.(0.68 mole) of freshly distilled [(CH N] 'PCl in 1200 ml. of petroleumether cooled to 55 to 60. The reaction mixture was stirred an additional15 minutes and then 50 ml. of dry ethyl ether was added to the reactionmixture to insure complete reaction. This caused the reaction mixture towarm quickly to 30 even though the reaction vessel was immersed in a 78cooling bath. The reaction mixture gradually cooled to -70". Another ml.of ethyl ether was then added and the reaction mixture gradually allowedto warm to room temperature (3 hours) and allowed to stand overnight.The reaction mixture was then brought to reflux and 26 g. (0.6 mole)of'(CI-I NH was addedto destroy any residual [(CHQ Nl PCl. The reactionmixture was then cooled to room temperature, filtered, and solvent re:moved by distillation to reduce the volume to about 300 ml. Upon coolingin an ice bath, a yield of 138g. of colorless needles was obtained. Thefiltrate was distilled and yielded 32.9 g. (0.20 mole) of [(CH N] P(B.P. -6061 at 18 mm.; percent N, found 25.4;calc. 25.75) plus anadditional 3.33 g. of colorless crystalline mate: rial. Hot tolueneextraction of'the filter cake from the reaction mixture yielded anadditional 14.0 g. of crystalline solid. Several recrystallizations ofasmallsample of the solid yielded a material, M.P. 146.5-147.5, whichanalyzed N, 17.72; C, 57.37; H, 8.99; calc. for

s 4( 3)2 '2)2 I N, 17.82; C, 53.49; H, 8.98. Total yield 31 g. (48percent).

A 3.0137 g. (0.09587 mole) sample of the recrystallizedp-bis[bis(dimethylamino)phosphino]benzene so prepared was suspended in50 ml. dry ethyl ether at '-78 C. A total of 17 31.4-cc. (100.7 percent)of anhydrous HCl was added in 3 nearly equal portions. The reactionmixture was allowed to warm to room temperature between each addition ofI-ICl. After the complete addition of HCl the reaction was allowedto'warm to room temperature and removal of the ether by distillationand'drying under mide Grignard reagent.

vacuum 2.268 g. (85 percent) of colorless crystallinep-bis(dichlorophosphino)benzene were obtained M.P. 5860.Recrystallization from dry petroleum ether yielded a material thatanalyzed: Cl, 49.7; C, 26.32; H, 2.00; calcd. for C H P Cl Cl, 50.7; C,25.75; H, 1.43.

EXAMPLE VI A 500 ml. ether solution of 136 g. (0.93 mole) of (CH NPCland a 600 ml. ether solution of the double ,1.

Grignard reagent made from 200 g. of 1,4-dibromobutane weresimultaneously added to 500 ml. ether, well stirred under dry nitrogenin a 2-liter 3-neck flask at 78' C. During the 2 hour period ofintroducing the reactants, the aminophosphorus chloride was kept inslight excess. The double Grignard solution tended to crystallize to ahard mass in the dropping funnel but was kept fluid through the use ofan infra-red lamp.

The reaction produced a crystal mass which was stirred at 78 C. for anhour and then allowed to warm to room temperature during an additionalhour. The loosely crystalline material then melted to a light brown,gummy mass which could not be stirred. After one hour of refluxing, theether solution was decanted from the gum and the ether removed bydistillation through a Vigreaux column. 9 g. of C H PN(CH were isolatedby high vacuum distillation.

A by-product was obtained by returning the ether to the non-volatileresidue and treating it with ammonia (200 g.) until there was no morewarming and the gum had become crystalline. The filtered ether solutionwas now evaporated, yielding about 1 g. of the C H PN(CH and some 30 g.of a higher boiling liquid.

The 1 g. fraction was not pure sample, for the methyl iodide adduct(obtained by direct mixing) gave a higher than expected halide analysis.A sample of the 9 g. product from the ice reflux fractionation of thedouble Grignard product, as described above, was measured as 27.95 cc.of standard gas and weighed as 172.2 mg. Thus, the observed molecularweight was 138.0; calc. 131.6. This sample was then put'through'aprocess'of conversion to C H PC1 by reaction with HCl. The 27.95 cc.sample absorbed 72.1 cc. of a 73.5 cc. sample of I-ICl, producing anonvolatile solid and a volatile liquid. The molecular weight of theliquid product was measured as 130; calculated for C H PCl, 122.5. Itmay have contained a little of the ring phosphinamine, for the 23.3 cc.sample absorbed only 42.9 cc. of diethylamine in restoring the originalcompound according to the equation,

The chlorine determination on the nonvolatile product ran 32 percenthigh accounting for the excess use of the HCl in the formation of the CH PC1.

EXAMPLE VII In the fashion set forth above, (Example II), 13.21 g.(0.120 mole) [(CH N] PC1 was placed in 300 ml. diethyl ether. To thiswas added 0.121 mole (18.91 g.) of C H MgBr in 300 m1. diethyl ether.The reaction was allowed to proceed at room temperature. The prodnot waspurified in a molecular still. Thereafter 0.071 mole of C H P[N(CH(11.72 g.) in 75 ml. (C H O was treated with 0.284 mole anhydrous HCl.After removal of diethylammonium chloride the solvent was stripped fromthe filtrate. The product, C H PCl boiling at l57160 C., was isolated byfractional distillation.

EXAMPLE VIII In fashion analogous to that set forth above, theaminophosphine i-C H P [N(CH 1 was prepared from approximately equalmolar quantities of the bis(dimethylamino)chlorophosphine and theisoamyl magnesium bro- The yield was 7.99 g. (0.042 mole). This, inturn, was dissolved in 100 ml. diethyl ether and treated with 0.168 moleanhydrous HCl. In the manner described above, the by-productdimethylammonium salt was removed by filtration and the solvent wasstripped from the ethereal filtrate. The product, i-C H PCl was isolatedby fractional condensation at 31 C. as in'Example III.

EXAMPLE IX In the fashion of Example VII the material C H MgBr wasreacted with bis(dimethylamino)chlorophosphine. The product, C H P [N(CHin the amount of 0.14 mole in 80 ml. diethyl ether was treated with 0.56mole anhydrous HBr. The diethylammonium bromide was removed from themixture by filtration and the product, C H PBr isolated by fractionaldistillation, at reduced pressure, B 8095 C.

EXAMPLE X I Using the procedure set forth above, C H PBr was prepared bytreating 0.083 mole C H P[N(CH (16.698 g.) in 75ml. diethyl ether with0.252 moles anhydrous HBr. The product, C H PBr B. 2557 C. was

isolated following removal of the dimethylamrnonium bromide.

EXAMPLE XI In substantially the same manner, 24.5 g. (0.158 mole)bis(dimethylamino)phenylphosphine in 60 ml. diethyl ether was treatedwith 0.632 mole anhydrous HI. The dimethylamrnonium iodide was removedfrom the reaction mixture and the product isolated by fractionaldistillation. The product, C H PI was obtained as a crude solid.

EXAMPLE XII to warm to room temperature and the ether thereafter removedby distillation. In the fashion set forth in Example III above, thelithium salts were precipitated and the mixture filtered. Thebis(dimethylamino)naphthyl- 'phosphine in the amount of 0.074 mole(18.23 g.) was dissolved in ml. (C H O and thereafter'treated 7 with0.296 mole anhydrous HCl. On fractional ,distillation of the reactionmixture a fair yield of i-C10H7Pc12 was obtained, B. 180, M. 589.

EXAMPLE XIII filtered from the solution and thedinaphthylchlorophosphine, (l-C H PCl, B. 270-80" C., removed from thesolvent by fractional distillation. The compound (l-C H PBr, melting at29-30" 0., 13. zen-300 c.,

was prepared from the same aminophosphine and hydro- In a fashlon511111131 to that set forth 111 Example XII bromic acid by reaction of21.43 mmoles of the former above, thebis(dimethylamino)naphthylphosphine was i h 4137 mmoles f h l treatedWith HBr to yield l-c H PBr 6.65 g. (0.027 mole) of C H P[N(CH weretreated with 0.108 7 EXAMPLE XIX mole anhydrous 10 p-Bis[bis(dimethylamino)phosphinolbenzene EXA V MPLE m P- s 4( (C s)2 2)2 A95 E F was prepared as set out in Example V above. Thereafter es) I g 813.97 g. 45 mmoles) were treated with 29.13 g. (360 1 g i e ow T 6 3mmoles) anhydrous HBr in 350 ml. diethyl ether. After 51 g warm; 2 g ghE removal of the by-product, dimethylammonium bromide, remove an mm to e3) 2 5 the solvent was stripped from the filtrate. The product, EXAMPLEXV p-bis(dibromophosphino)benzene, p-C H (PBr was isolated bydistillation in the molecular still.

A3489 g. sample of (CH NP(C H (26.2 mmoles) Results of additional runsare set forth in the table was treated with 52.5 mmoles of HBr.Initially the rewhich follows:

HX Example Aminohalo- Grignard Reagent Aminophosphine Mols Grams ProductPhosphine X Mols action vessel was cooled to less than 65 C. and,following completion of the reaction, the volatile product was removedand found to be (C H PBr, 13. 130-35 C.

EXAMPLE XVI EXAMPLE XVII To a well-stirred solution of 0.201 mole (CHNPCl in 400 ml. diethyl ether was added 0.402 mole C I-I MgBr, also in400 ml. diethyl ether. The product,

was purified as set forth in Example II above and thereafter 8.213 g.(0.0541 mole) of this material Were placed in 50 ml. diethyl ether andallowed to react with 0.109 mole HBr. The by-product was removed and theproduct (C H PBr, isolated by fractional distillation, 13. 183-84 C.

EXAMPLE XVIII Dimethylaminodinaphthylphosphine,

in the amount of 8.563 g. (26.0 mmole) was dissolved in 50 ml. diethylether. Thereafter 52.8 g. mmoles HCl were bubbled into the solution. Thereaction occurred vigorously, following which time the by-product wasThe use of the compounds of the process of this invention containingonly a single phosphorus atom to produce phosphinoborine compounds isset forth in US. Patent No. 2,892,873. The reaction described thereininvolves the monofunctional halophosphines of this invention and alkalimetal borohydrides to yield metallic halides and phosphine borinecompounds of the formula R representing a hydrocarbon group and Rrepresenting H or a hydrocarbon group. When heated to a temperature ofbetween about 100 and 200 C., the phosphine borines lose hydrogen toyield phosphinoborines of the formula [R PBHCH These phosphinoborineproducts find utility as dielectrics. The use of diphosphines disclosedherein to produce difuuctional phosphinoborines is set forth in ourco-pending application Serial No.

695,230, filed November 8, 1957. As described therein, compounds of thetype R(PH may be prepared by reducing with lithium aluminum hydridecompounds of the type R(PX Any of the methods customarily used in thereduction of monofunctional organohalophosphines may be used also. Thenonhalogenated intermediates may then be treated with sodium inequimolar quantities to yield a compound of the formula H PRPNa whichthereafter is treated with an alkyl halide (RX) to yield a compound ofthe formula H PRPHR. This in turn is treated again with an equimolarportion of sodium to form NaI-IPRPHR, which is further treated withadditional alkyl halide (R"X) to yield a compound of the formulaR"HPRPHR. This difunctional phosphine material is treated with diboranein equimolar quantities to yield a phosphine borine of the formula HB:PH(R)R(R")HP:BH which may be pyrolyzed at 350 C. to yield aphosphinoborine of the formula [H PB(R)R(R")PHB by driving ofi hydrogenfrom the phosphine borine. The reaction is carried out in accordancewith the details set forth in the copending application Serial No.695,230. As set forth there, the phosphinoborines so obtained displayexcellent dielectric properties and are thermally resistant. Thus, suchphosphinoborines find utility where thermally and chemically resistantdielectrics are required.

Obviously manymodifications and variations of the invention ashereinbefore set forth may be made Without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A compound of the general formula:

wherein Y is selected from the group consisting of arylene,tetramethylene, pentamethylene and hexamethylene, and wherein X is ahalogen selected from the group consisting of Cl, Br and I.

2. Compounds of the formula: (CH ),,(PX where n is 4-6 and X is halogenfrom the group consisting of chlorine, bromine and iodine.

p-Bis(dichlorophosphino)benzene. p-Bis(dibromophosphino)benzene.1,4-bis(dichlorophosphino)butane. 1,5-bis(dichlorophosphino)pentane.1,6-bis(dichlorophosphino)hexane. The process for the preparation ofhalophosphines comprising: treating an aminophosphine with h drohalogenacid in about the stoichiometric quantity necessary to replace eachofthe amino groups on said aminophosphine with a halogen.

9. The process of claim 8 wherein the aminophosphine isdimethylaminodimethylphosphine and wherein the product isdimethylchlorophosphine.

10. The process of claim 8 wherein the aminophosphine isdimethylaminocyclotetramethylenephosphine and wherein the product iscyclotetramethylenechlorophosphine.

11. The process of claim 8 wherein the aminophosphine isdimethylaminodi-p-tolylphosphine and wherein the product isdi-p-tolylchlorophosphine.

12. The process of claim 8 wherein the aminophosphine isbis(dimethylamino)phenylphosphine and wherein the product isphenyldichlorophosphine.

13. The process of claim 8 wherein the aminophosphine is p-bis [bisdimethylamino phosphino 1 benzene and wherein the product isp-bis(dichlorophosphino)benzene.

References Cited in the file of this patent UNITED STATES PATENTS2,437,796 Walling Mar. 16, 1948 2,437,798 Walling Mar. 16, 19482,615,043 Kharasch et a1. Oct. 21, 1952 2,662,917 Jensen Dec. 15, 1953OTHER REFERENCES Kosalapoff: Organo Phosphorus Compounds, pgs. 53- 55(1950).

1. A COMPOUND OF THE GENERAL FORMULA: